Builds The LF40 Wheeler Build - Twin Turbo & 8 Speed Auto FJ40 (3 Viewers)

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Alright, update time!

I've been working out a new drivetrain for this, and I think that I finally have come to a resolution. I really want to do something different, modern, turbo'd, and very driveable, kinda like @Godfather90 has with his TDI. I'm also wanting to go auto for the driveability and crawling. I know I discussed this a bit earlier, but anyway, here is what I'm thinking.

Diesel seems like a good option, but I don't want to have to deal with one in the cold at school. It is averaging around -20 - -30 from Dec to February, and I don't really have the option to plug it in.

I also want something relatively efficient, so smaller displacement and a smaller block to fit better in a 40.

So, what have I found with those requirements? GM has a very niche little lineup in a few select Cadillac models, mainly the ATS and CTS - V lineups. They are Twin Turbo, 3.6 liter v6 engines mated to 6l90s, 8l90s, and 8l45s. The LF4 and LF3 are extremely power-dense engines, making 455 HP and 445 TQ and 420 HP and 430 TQ respectively. They have manifold-based water-to-air intercoolers, which is great, as I don't have to shove a massive air-to-air intercooler in front of a 40.

I'm planning on using an LF4, as it came with the 8l90 from the factory. This means I can directly mate an Atlas transfer case to the trans, solving that issue.

There are several other features of the LF4, including an extremely overbuilt bottom end, featuring forged everything and titanium connecting rods, sleeved cylinders, DOHC, and twin scroll chargers that do not add any width to the block and offer no-lag boost. People have been pushing 700+ WHP with the stock bottom end on this engine.


I have been talking to a few different guys that have swapped and created standalone LF4s. It is very doable with minimal harness modification, and an ECU flash with HP tuners. It's a pretty rare swap, but they have been getting great economy and power out of this engine.

Anyways, I know the 8l90 has some problems, but a factory trans and engine is what I believe is the best thing possible for reliability and driveability. I'm planning on either adding paddles or a bump shifter to the trans, giving full control over it.

So, I would love to hear your guy's thoughts on this swap. I get that it will be pretty difficult, but I want to try something different, and hopefully get a super fun swap out of it.
Do it! if you can handle the budget then i bet it would be a really good combo in a 40. probably cheaper swaps for the HP but it would definitely be different and probably let you push the whole drive train forward some to help with rear driveshaft length.
 
Do it! if you can handle the budget then i bet it would be a really good combo in a 40. probably cheaper swaps for the HP but it would definitely be different and probably let you push the whole drive train forward some to help with rear driveshaft length.

That's a big reason I want a higher power v6 over a v8. Its shorter. Also a lot less displacement (and fuel burned) too.
 
That's a big reason I want a higher power v6 over a v8. Its shorter. Also a lot less displacement (and fuel burned) too.
I’m curious about hat mileage. I have a friend that had a ‘boost f150, said it was alright when you had your foot out of it, but as soon as the whistling started mileage dropped. I’ve got a completely different build coming up and the ecoboost is on the list. Possibly just for the cool factor. Caddi opens up more possibilities…
 
That's a big reason I want a higher power v6 over a v8. Its shorter. Also a lot less displacement (and fuel burned) too.
I wouldn't bank on much better fuel mileage just from smaller displacement seeing as you are still turning heavy 37" tires and pushing a vehicle that has the aerodynamics of a brick house. unless you go diesel. They have a higher internal efficiency vs gasoline motors. the new direct injected motors are closing that gap some though.
 
I wouldn't bank on much better fuel mileage just from smaller displacement seeing as you are still turning heavy 37" tires and pushing a vehicle that has the aerodynamics of a brick house. unless you go diesel. They have a higher internal efficiency vs gasoline motors. the new direct injected motors are closing that gap some though.

It'll be better than the 8-10 i'm averaging now, I'll bet.
 
It'll be better than the 8-10 i'm averaging now, I'll bet.
yeah a little, but i would not guess much more than 12. Unless you can drive 55 unlike ZZ top.

end of the day it is about smiles per mile though.
 
yeah a little, but i would not guess much more than 12. Unless you can drive 55 unlike ZZ top.

end of the day it is about smiles per mile though.

We'll see, I guess. They have about a 21 combined, so it may be around there, it may be a bit higher. I'm also looking at the 2.8 Duramax / 8l90 combo as well with @Godfather90. I'd like to run that if I could, but it is a problem of tuning the ECU and cleaning up the harness which I am trying to figure out as well.
 
That's really bad gas mileage. Perhaps it's running too rich and timing isn't advanced enough?

Been playing with the tune. I think there is a bit of overlap on the cam which is not helping at all, but I've pushed timing about as far as I am comfortable with the quick burn heads that are on there, and wayyy leaned everything out. It's doing better for sure, but I haven't put enough miles on to really see how much better it is.
 
Been playing with the tune. I think there is a bit of overlap on the cam which is not helping at all, but I've pushed timing about as far as I am comfortable with the quick burn heads that are on there, and wayyy leaned everything out. It's doing better for sure, but I haven't put enough miles on to really see how much better it is.
Typically at highway cruise you can run a lot of advance which is part of a tune many pay little attention too but can give increased mpg. Power enrichment can be set much later in the throttle position which can also help mileage a lot. I'm not sure how much control you have with your setup though as far as programming.
 
Well, a 3.8 atlas to mate to an 8l90 has been ordered. Expected delivery by July 1st. 🙃

Now to get the rest.....
 
Well, it's my last day of spring break, so I thought I'd give an update.

I went home for a few days for a dentist appointment and to see my parents, and I got the cruiser prepped for Cruise Moab.

New front fender rubber to stop me from flinging stuff everywhere. It helps a ton.

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New coilovers for the rear. King 2.0, 12", with compression adjusters. I'm planning on a 1:1.2 rear cantilever suspension and mounting these laterally in the wheel wells. Should give me about 14" of rear travel, without cutting my floor.

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Got the cruiser out for a bit, and took some pictures. My rear arb either hates the cold, or has a completely blow seal, and just pumps out air now. Luckily it still locks. I'm just hoping the cold weather shrunk something enough that it will seal better when warm.

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I then headed up to the shop for a while. Worked at the shop for 4 days, put in 55 hours. Got a lot done, though.

I was requested to deliver about 10K worth of champagne for a client at the shop. It was not the most fun drive I've had.

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Got a ton of stuff prepped for the new shop build, and got the chassis, suspention, and axles reassembled after paint and zinc.

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Got to see the shop sausage.

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And got the new shop swag hoodie. It's sick.

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Anyways, that's what I've been up to.
 
Well, it's an end of an era for this cruiser. Time to bring it into the modern age. The last run on this current drivetrain was Hell's Revenge at Cruise Moab.

Here is a link to all the photos from Cruise Moab: Cruise Moab 2022 - Google Drive - https://drive.google.com/drive/folders/1JGdAlz08GJ-SChJ7A9wchd7H8n1iwdPC?usp=sharing. There are some great videos of the Megacruiser and others in there as well.

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Later that night, this fell out.

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It's heading off to California to @zidaro in his new build.

It was an awesome time, and it's been exactly 1 year since this cruiser first started running. Kind of bittersweet since I put a ton of time into this build and it's basically starting again (besides the body).

So what's up with the new name? I decided this thing needed a new name, and the new engine going in fits the description pretty well. for those who didn't read a few pages ago, the cruiser is getting a 2016 LF4, 8l90, and 3.8 Atlas, along with a new rear suspension. LF40 fits pretty well, I think.

The LF4 is a Twin Turbo, 3.6 liter v6 engine mated to an 8l90 and is an extremely power-dense engine, making 455 HP and 445 TQ. They have manifold-based water-to-air intercoolers, which is great, as I don't have to shove a massive air-to-air intercooler in front of a 40. It's also about 6" shorter than an LS-based engine.

There are several other features of the LF4, including an extremely overbuilt bottom end, featuring forged everything and titanium connecting rods, sleeved cylinders, DOHC, and twin scroll chargers that do not add any width to the block and offer no-lag boost. People have been pushing 700+ WHP with the stock bottom end on this engine.

Anyways, I have the LF4, 8l90, and the Atlas is supposed to be here in about 2 months. New King 2.0 12"s for the rear, and most of my time for the summer besides work. anyways, this thing is going to scoot.
 
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Well, it's an end of an era for this cruiser. Time to bring it into the modern age. The last run on this current drivetrain was Hell's Revenge at Cruise Moab.

Here is a link to all the photos from Cruise Moab: Cruise Moab 2022 - Google Drive - https://drive.google.com/drive/folders/1JGdAlz08GJ-SChJ7A9wchd7H8n1iwdPC?usp=sharing. There are some great videos of the Megacruiser and others in there as well.

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Later that night, this fell out.

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It's heading off to California to @zidaro in his new build.

It was an awesome time, and it's been exactly 1 year since this cruiser first started running. Kind of bittersweet since I put a ton of time into this build and it's basically starting again (besides the body).

So what's up with the new name? I decided this thing needed a new name, and the new engine going in fits the description pretty well. for those who didn't read a few pages ago, the cruiser is getting a 2016 LF4, 8l90, and 3.8 Atlas, along with a new rear suspension. LF40 fits pretty well, I think.

The LF4 is a Twin Turbo, 3.6 liter v6 engine mated to an 8l90 and is an extremely power-dense engine, making 455 HP and 445 TQ. They have manifold-based water-to-air intercoolers, which is great, as I don't have to shove a massive air-to-air intercooler in front of a 40. It's also about 6" shorter than an LS-based engine.

There are several other features of the LF4, including an extremely overbuilt bottom end, featuring forged everything and titanium connecting rods, sleeved cylinders, DOHC, and twin scroll chargers that do not add any width to the block and offer no-lag boost. People have been pushing 700+ WHP with the stock bottom end on this engine.

Anyways, I have the LF4, 8l90, and the Atlas is supposed to be here in about 2 months. New King 2.0 12"s for the rear, and most of my time for the summer besides work. anyways, this thing is going to scoot.
I missed the choice of engine and trans earlier I guess. This thing is going to be extremely radical! Where did you pick up the engine/trans combo, is it complete with harness and ECU, ie, all factory controls? Is the trans the factory trans for that engine, or did you source a 4x4 unit? If factory, how easy is it to convert to mate up to the Atlas?
 
I missed the choice of engine and trans earlier I guess. This thing is going to be extremely radical! Where did you pick up the engine/trans combo, is it complete with harness and ECU, ie, all factory controls? Is the trans the factory trans for that engine, or did you source a 4x4 unit? If factory, how easy is it to convert to mate up to the Atlas?

LF4 and 8l90 are mated stock and 2wd from factory, but AA makes an adapter that just bolts it up to the atlas (supposedly, so we will see) and is 3/4" thick. I got a complete engine and trans (also supposedly) from ebay. Just need to get the water to air intercooler stuff. I have a guy that will clean up the factory harness and make it standalone. I'm either going to add bump shift or paddles, not sure yet. The 8l90 supports either.
 
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watching intently
 

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